Tool Holder Bit Retention via Austenitic Socket and Pusher

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Solution Overview

Problem

Existing tool holding devices for power tools often require elongated bits to prevent wobble and securely retain the bit, but these devices fail to securely hold the bit in place without user intervention, leading to inconvenience and potential loss of the bit due to gravity, and existing magnetic solutions are weakened by magnetizable materials.

Innovation Solution

A tool holding device featuring a socket made of austenitic stainless steel with a magnet and a pusher mechanism, where the pusher is biased by a resilient member to securely retain the bit and prevent it from falling, and a sleeve that is axially and rotatably movable to facilitate bit removal without scattering the magnetic force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a magnet is disposed in the toolholder to prevent the bit from falling out, then the bit can be retained without user intervention, but the magnetic force is scattered and weakened by magnetizable materials in the toolholder and other elements

Engineering Contradiction:
Improvebit retentionVSAvoidmagnetic force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

A non-magnetizable intermediary component (the socket made of austenitic stainless steel) is introduced between the magnet and the bit. This intermediary prevents the magnetic force from being scattered by magnetizable materials in the toolholder structure, allowing the magnet to effectively retain the bit without losing strength to surrounding magnetic materials.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The material parameter of the socket is changed from a magnetizable material to austenitic stainless steel, which is non-magnetizable. This parameter change ensures that the magnetic field generated by the magnet is not disrupted or scattered by the socket material, maintaining the magnetic force's effectiveness for bit retention.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the toolholder structure includes magnetizable materials, then the structural integrity and manufacturing are simplified, but the magnetic force is scattered and weakened

Engineering Contradiction:
Improvetoolholder manufacturingVSAvoidmagnetic force
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The material parameter of the socket is specifically changed to austenitic stainless steel, which has the property of being non-magnetizable. This material selection resolves the contradiction by providing a structurally sound component that does not interfere with the magnetic field, allowing both easy manufacturing and effective magnetic retention.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a pusher mechanism is added to facilitate bit removal, then bit removal is easier and more automated, but the device complexity increases

Engineering Contradiction:
Improvebit removalVSAvoidtoolholder structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The pusher mechanism is designed to be automatically actuated by the sleeve's axial movement. When the user moves the sleeve axially, the pusher automatically pushes the bit out without requiring the user to manually grasp and remove the bit. This self-service mechanism simplifies operation while keeping the added complexity minimal.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The pusher acts as an intermediary component that translates the sleeve's axial movement into bit ejection. This intermediary mechanism facilitates automatic bit removal, improving ease of operation while maintaining relatively simple device architecture through a single additional component.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Force

If the socket is made of austenitic stainless steel, then the magnetic force is maintained effectively, but the material cost and manufacturing complexity may increase

Engineering Contradiction:
Improvemagnetic forceVSAvoidsocket manufacturing
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

The material parameter of the socket is changed to austenitic stainless steel, which provides the necessary non-magnetizable property. While this may increase material cost slightly, it eliminates the need for complex magnetic shielding designs or multiple component assemblies, potentially simplifying the overall manufacturing process.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The device effectively reduces the need for elongated bits, securely holds the bit in place, and allows for easy removal without user intervention, maintaining the magnetic force's effectiveness by using non-magnetizable materials for the pusher.

Implementation Method 1

U.S. Pat. No. 6,345,560 teaches a magnet, which is disposed in the toolholder adapted to relieve this problem

Methodology Applied
Scientific EffectMagnetism: Magnetism

Implementation Method 2

A resilient member is disposed in the hole as to bias the pusher in the hole

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2517836B1Tool holding device
Publication Date: 2014.05.14 HU BOBBY
  • EP2517836B1 patent drawingFigure 1
  • EP2517836B1 patent drawingFigure 2
  • EP2517836B1 patent drawingFigure 3

AI summary

A tool holding device is suitable to have an application with a power tool. The tool holding device includes a toolholder (10) for receiving a bit (93). A sleeve (20, 20A) is disposed outside the toolholder (10) and is operable to move between a first position which allows for removal of the bit (93) and a second position which allows the bit to be securely retained in the cavity (14A, 14B, 14C, 14D, 14E) of the toolholder (10). A returning member (40) is disposed circumferentially between the toolholder (10) and the second section of the sleeve (23) for returning the sleeve (23) to the second position. Moreover, the portion of the sleeve (23) which does not surround the returning member (40) abuts the toolholder (10).